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Full text of "Rapid Population Growth Consequences And Policy Implications"

females, and the chance of living to age 50 for a boy just born is 0.741, and for a girl 0.764. These mortality figures contrast sharply with those for Madagascar though births for the two countries are at about the same level. A country with a birth rate of about 44 per 1,000 and a death rate of about 9 will grow at 3.5 percent per year. Such a country would double its population in 20 years. Honduras is not the only country apparently in this condition; Mexico's rates of birth and death are within 1 per 1,000 of Honduras, and so are those of many other countries. The real number of births in these countries may be even higher than registered births. For this group as a whole we may speak conservatively of a birth rate of 40 per 1,000 and a death rate of 10 per 1,000, a growth by natural increase of 3 percent per year. Again we cannot say with precision how much of the world is in this condition, but it is certainly more than half; let us say that it includes around 2 billion people. One way to see the meaning of a rate of increase is to translate it into doubling time t, obtained as the solution of the equation (1 + r)< = 2, where r is the fraction of increase per year. The solution for f, obtained by taking natural logarithms, is _ In 2 _ 0.693 t — — . - 2 r2/2 r - r2/2 if terms in r3 and higher may be disregarded, or very nearly t = 0.70/r for values of r in the range 0 to 0.04. Hence the rule that doubling time is obtained bv dividing the percentage annual increase into 70; on this rule Honduras' annual 3.5 percent implies a doubling time of 70/3.5 = 20 years. On the 2 percent increase of Madagascar the doubling time is 35 years. On the 0.5 percent of Sweden in 1800 the doubling time is 140 years. Thus over the course of 140 years Honduras would have seven doublings: it would multiply by 27 = 128 times. In the same 140 years Madagascar would double 4 times, a multiplication by 16. And Sweden of 1800 would multiply only by 2. Although the rates of increase 3.5 percent, 2 percent, and 0.5 percent do not seem very different, the numbers 128, 16, and 2 as factors are different indeed. Sweden could continue at the 0.5 percent rate, and indeed it doubled in about 90 years, despite emigration, because of a fall in its death rate. Honduras-with its spatial and other limitations— cannot double seven times in 140 years or any other period, for this increase would cause it to pass the quarter billion mark. Such considerations make us certain that the rate for Honduras cannot continue; either the birth rate will come down or the death rate will go up.males and 60.7 for oo-f ;,•>-,<> too r\f Kit-tin fjfao tr\ lio. Because some women die after the age of 20 and before 40, the reduction of the birth rate at the younger age will have more consequence for the rate of natural increase. For a population that is rapidly increasing, however, this is lessh to prove troublesome. control. Dr. Hilton Salhanick has observed that some women practicing the rhythm method will break or lose their thermometers at the critical juncture in theirright, therefore alwayshas some c